ISSN:
1615-6102
Keywords:
β-amylase
;
Barley endosperm
;
Bound β-amylase
;
Free β-amylase
;
Seed desiccation
;
Starch granules
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Association of β-amylase with starch granules in the starchy endosperm of barley (Hordeum vulgare L. cv. Menuet) grains was characterized biochemically. In whole homogenates of dry seeds, two forms of β-amylase were detected: one is free β-amylase extractable with saline solution and the other is bound β-amylase extractable with saline solution containing a reducing agent. The two forms of β-amylase were shown to be identical in terms of mobility on disc gels, antigenicity, and molecular specific activity, indicating that the β-amylase molecules of the two forms are identical. The starch granules were isolated from either dry seeds or mature seeds harvested before the desiccation phase. Both starch granule preparations were morphologically identical by microscopic inspection. The bound β-amylase was predominantly associated with starch granules isolated from dry seeds, whereas it was not associated with starch granules from mature seeds harvested before desiccation. Overall results show that the periphery of starch granules is the major site of deposition for bound β-amylase in dry seeds. The association of β-amylase with starch granules occurs during the desiccation phase of seed development, resulting in the conversion of free β-amylase into a bound form.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01275713
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